Jonny Evans has a £3m relegation release clause in his West Brom contract, Sky Sports News understands.
It means that West Brom, who are 19th in the table with just one win from their last 22 Premier League games, risk losing him for next to nothing this summer should they drop into the Sky Bet Championship.
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The 30-year-old has 18 months remaining on his contract and Manchester City and Arsenal have made enquiries this month for the Northern Ireland defender.
However, Sky Sports News understands that there has still been no further contact from City, Arsenal or any other club since those two made the initial enquiries in the first few days of the window.
Evans started his career at Manchester United and won three Premier League titles before joining West Brom in August 2015.
He has made 22 appearances for the Baggies this season.